fs/quota/quota.c

   1 /*
   2  * Quota code necessary even when VFS quota support is not compiled
   3  * into the kernel.  The interesting stuff is over in dquot.c, here
   4  * we have symbols for initial quotactl(2) handling, the sysctl(2)
   5  * variables, etc - things needed even when quota support disabled.
   6  */
   7
   8 #include <linux/fs.h>
   9 #include <linux/namei.h>
  10 #include <linux/slab.h>
  11 #include <asm/current.h>
  12 #include <asm/uaccess.h>
  13 #include <linux/compat.h>
  14 #include <linux/kernel.h>
  15 #include <linux/security.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/buffer_head.h>
  18 #include <linux/capability.h>
  19 #include <linux/quotaops.h>
  20 #include <linux/types.h>
  21 #include <net/netlink.h>
  22 #include <net/genetlink.h>
  23
  24 /* Check validity of generic quotactl commands */
  25 static int generic_quotactl_valid(struct super_block *sb, int type, int cmd,
  26                                   qid_t id)
  27 {
  28         if (type >= MAXQUOTAS)
  29                 return -EINVAL;
  30         if (!sb && cmd != Q_SYNC)
  31                 return -ENODEV;
  32         /* Is operation supported? */
  33         if (sb && !sb->s_qcop)
  34                 return -ENOSYS;
  35
  36         /* Check privileges */
  37         if (cmd == Q_GETQUOTA) {
  38                 if (((type == USRQUOTA && current_euid() != id) ||
  39                      (type == GRPQUOTA && !in_egroup_p(id))) &&
  40                     !capable(CAP_SYS_ADMIN))
  41                         return -EPERM;
  42         }
  43         else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
  44                 if (!capable(CAP_SYS_ADMIN))
  45                         return -EPERM;
  46
  47         return 0;
  48 }
  49
  50 /* Check validity of XFS Quota Manager commands */
  51 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd,
  52                               qid_t id)
  53 {
  54         if (type >= XQM_MAXQUOTAS)
  55                 return -EINVAL;
  56         if (!sb)
  57                 return -ENODEV;
  58         if (!sb->s_qcop)
  59                 return -ENOSYS;
  60
  61         /* Check privileges */
  62         if (cmd == Q_XGETQUOTA) {
  63                 if (((type == XQM_USRQUOTA && current_euid() != id) ||
  64                      (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
  65                      !capable(CAP_SYS_ADMIN))
  66                         return -EPERM;
  67         } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
  68                 if (!capable(CAP_SYS_ADMIN))
  69                         return -EPERM;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int check_quotactl_valid(struct super_block *sb, int type, int cmd,
  76                                 qid_t id)
  77 {
  78         int error;
  79
  80         if (XQM_COMMAND(cmd))
  81                 error = xqm_quotactl_valid(sb, type, cmd, id);
  82         else
  83                 error = generic_quotactl_valid(sb, type, cmd, id);
  84         if (!error)
  85                 error = security_quotactl(cmd, type, id, sb);
  86         return error;
  87 }
  88
  89 #ifdef CONFIG_QUOTA
  90 void sync_quota_sb(struct super_block *sb, int type)
  91 {
  92         int cnt;
  93
  94         if (!sb->s_qcop->quota_sync)
  95                 return;
  96
  97         sb->s_qcop->quota_sync(sb, type);
  98
  99         if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
 100                 return;
 101         /* This is not very clever (and fast) but currently I don't know about
 102          * any other simple way of getting quota data to disk and we must get
 103          * them there for userspace to be visible... */
 104         if (sb->s_op->sync_fs)
 105                 sb->s_op->sync_fs(sb, 1);
 106         sync_blockdev(sb->s_bdev);
 107
 108         /*
 109          * Now when everything is written we can discard the pagecache so
 110          * that userspace sees the changes.
 111          */
 112         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
 113         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 114                 if (type != -1 && cnt != type)
 115                         continue;
 116                 if (!sb_has_quota_active(sb, cnt))
 117                         continue;
 118                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
 119                                   I_MUTEX_QUOTA);
 120                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
 121                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
 122         }
 123         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
 124 }
 125 #endif
 126
 127 static void sync_dquots(int type)
 128 {
 129         struct super_block *sb;
 130         int cnt;
 131
 132         spin_lock(&sb_lock);
 133 restart:
 134         list_for_each_entry(sb, &super_blocks, s_list) {
 135                 /* This test just improves performance so it needn't be
 136                  * reliable... */
 137                 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 138                         if (type != -1 && type != cnt)
 139                                 continue;
 140                         if (!sb_has_quota_active(sb, cnt))
 141                                 continue;
 142                         if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
 143                            list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
 144                                 continue;
 145                         break;
 146                 }
 147                 if (cnt == MAXQUOTAS)
 148                         continue;
 149                 sb->s_count++;
 150                 spin_unlock(&sb_lock);
 151                 down_read(&sb->s_umount);
 152                 if (sb->s_root)
 153                         sync_quota_sb(sb, type);
 154                 up_read(&sb->s_umount);
 155                 spin_lock(&sb_lock);
 156                 if (__put_super_and_need_restart(sb))
 157                         goto restart;
 158         }
 159         spin_unlock(&sb_lock);
 160 }
 161
 162 static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
 163                          void __user *addr)
 164 {
 165         char *pathname;
 166         int ret = -ENOSYS;
 167
 168         pathname = getname(addr);
 169         if (IS_ERR(pathname))
 170                 return PTR_ERR(pathname);
 171         if (sb->s_qcop->quota_on)
 172                 ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
 173         putname(pathname);
 174         return ret;
 175 }
 176
 177 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
 178 {
 179         __u32 fmt;
 180
 181         down_read(&sb_dqopt(sb)->dqptr_sem);
 182         if (!sb_has_quota_active(sb, type)) {
 183                 up_read(&sb_dqopt(sb)->dqptr_sem);
 184                 return -ESRCH;
 185         }
 186         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
 187         up_read(&sb_dqopt(sb)->dqptr_sem);
 188         if (copy_to_user(addr, &fmt, sizeof(fmt)))
 189                 return -EFAULT;
 190         return 0;
 191 }
 192
 193 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
 194 {
 195         struct if_dqinfo info;
 196         int ret;
 197
 198         if (!sb_has_quota_active(sb, type))
 199                 return -ESRCH;
 200         if (!sb->s_qcop->get_info)
 201                 return -ENOSYS;
 202         ret = sb->s_qcop->get_info(sb, type, &info);
 203         if (!ret && copy_to_user(addr, &info, sizeof(info)))
 204                 return -EFAULT;
 205         return ret;
 206 }
 207
 208 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
 209 {
 210         struct if_dqinfo info;
 211
 212         if (copy_from_user(&info, addr, sizeof(info)))
 213                 return -EFAULT;
 214         if (!sb_has_quota_active(sb, type))
 215                 return -ESRCH;
 216         if (!sb->s_qcop->set_info)
 217                 return -ENOSYS;
 218         return sb->s_qcop->set_info(sb, type, &info);
 219 }
 220
 221 static int quota_getquota(struct super_block *sb, int type, qid_t id,
 222                           void __user *addr)
 223 {
 224         struct if_dqblk idq;
 225         int ret;
 226
 227         if (!sb_has_quota_active(sb, type))
 228                 return -ESRCH;
 229         if (!sb->s_qcop->get_dqblk)
 230                 return -ENOSYS;
 231         ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
 232         if (ret)
 233                 return ret;
 234         if (copy_to_user(addr, &idq, sizeof(idq)))
 235                 return -EFAULT;
 236         return 0;
 237 }
 238
 239 static int quota_setquota(struct super_block *sb, int type, qid_t id,
 240                           void __user *addr)
 241 {
 242         struct if_dqblk idq;
 243
 244         if (copy_from_user(&idq, addr, sizeof(idq)))
 245                 return -EFAULT;
 246         if (!sb_has_quota_active(sb, type))
 247                 return -ESRCH;
 248         if (!sb->s_qcop->set_dqblk)
 249                 return -ENOSYS;
 250         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
 251 }
 252
 253 static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
 254 {
 255         __u32 flags;
 256
 257         if (copy_from_user(&flags, addr, sizeof(flags)))
 258                 return -EFAULT;
 259         if (!sb->s_qcop->set_xstate)
 260                 return -ENOSYS;
 261         return sb->s_qcop->set_xstate(sb, flags, cmd);
 262 }
 263
 264 static int quota_getxstate(struct super_block *sb, void __user *addr)
 265 {
 266         struct fs_quota_stat fqs;
 267         int ret;
 268
 269         if (!sb->s_qcop->get_xstate)
 270                 return -ENOSYS;
 271         ret = sb->s_qcop->get_xstate(sb, &fqs);
 272         if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
 273                 return -EFAULT;
 274         return ret;
 275 }
 276
 277 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
 278                            void __user *addr)
 279 {
 280         struct fs_disk_quota fdq;
 281
 282         if (copy_from_user(&fdq, addr, sizeof(fdq)))
 283                 return -EFAULT;
 284         if (!sb->s_qcop->set_xquota)
 285                 return -ENOSYS;
 286         return sb->s_qcop->set_xquota(sb, type, id, &fdq);
 287 }
 288
 289 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
 290                            void __user *addr)
 291 {
 292         struct fs_disk_quota fdq;
 293         int ret;
 294
 295         if (!sb->s_qcop->get_xquota)
 296                 return -ENOSYS;
 297         ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
 298         if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
 299                 return -EFAULT;
 300         return ret;
 301 }
 302
 303 /* Copy parameters and call proper function */
 304 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 305                        void __user *addr)
 306 {
 307         switch (cmd) {
 308         case Q_QUOTAON:
 309                 return quota_quotaon(sb, type, cmd, id, addr);
 310         case Q_QUOTAOFF:
 311                 if (!sb->s_qcop->quota_off)
 312                         return -ENOSYS;
 313                 return sb->s_qcop->quota_off(sb, type, 0);
 314         case Q_GETFMT:
 315                 return quota_getfmt(sb, type, addr);
 316         case Q_GETINFO:
 317                 return quota_getinfo(sb, type, addr);
 318         case Q_SETINFO:
 319                 return quota_setinfo(sb, type, addr);
 320         case Q_GETQUOTA:
 321                 return quota_getquota(sb, type, id, addr);
 322         case Q_SETQUOTA:
 323                 return quota_setquota(sb, type, id, addr);
 324         case Q_SYNC:
 325                 if (sb) {
 326                         if (!sb->s_qcop->quota_sync)
 327                                 return -ENOSYS;
 328                         sync_quota_sb(sb, type);
 329                 } else
 330                         sync_dquots(type);
 331                 return 0;
 332         case Q_XQUOTAON:
 333         case Q_XQUOTAOFF:
 334         case Q_XQUOTARM:
 335                 return quota_setxstate(sb, cmd, addr);
 336         case Q_XGETQSTAT:
 337                 return quota_getxstate(sb, addr);
 338         case Q_XSETQLIM:
 339                 return quota_setxquota(sb, type, id, addr);
 340         case Q_XGETQUOTA:
 341                 return quota_getxquota(sb, type, id, addr);
 342         case Q_XQUOTASYNC:
 343                 if (!sb->s_qcop->quota_sync)
 344                         return -ENOSYS;
 345                 return sb->s_qcop->quota_sync(sb, type);
 346         default:
 347                 return -EINVAL;
 348         }
 349 }
 350
 351 /*
 352  * look up a superblock on which quota ops will be performed
 353  * - use the name of a block device to find the superblock thereon
 354  */
 355 static struct super_block *quotactl_block(const char __user *special)
 356 {
 357 #ifdef CONFIG_BLOCK
 358         struct block_device *bdev;
 359         struct super_block *sb;
 360         char *tmp = getname(special);
 361
 362         if (IS_ERR(tmp))
 363                 return ERR_CAST(tmp);
 364         bdev = lookup_bdev(tmp);
 365         putname(tmp);
 366         if (IS_ERR(bdev))
 367                 return ERR_CAST(bdev);
 368         sb = get_super(bdev);
 369         bdput(bdev);
 370         if (!sb)
 371                 return ERR_PTR(-ENODEV);
 372
 373         return sb;
 374 #else
 375         return ERR_PTR(-ENODEV);
 376 #endif
 377 }
 378
 379 /*
 380  * This is the system call interface. This communicates with
 381  * the user-level programs. Currently this only supports diskquota
 382  * calls. Maybe we need to add the process quotas etc. in the future,
 383  * but we probably should use rlimits for that.
 384  */
 385 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 386                 qid_t, id, void __user *, addr)
 387 {
 388         uint cmds, type;
 389         struct super_block *sb = NULL;
 390         int ret;
 391
 392         cmds = cmd >> SUBCMDSHIFT;
 393         type = cmd & SUBCMDMASK;
 394
 395         if (cmds != Q_SYNC || special) {
 396                 sb = quotactl_block(special);
 397                 if (IS_ERR(sb))
 398                         return PTR_ERR(sb);
 399         }
 400
 401         ret = check_quotactl_valid(sb, type, cmds, id);
 402         if (ret >= 0)
 403                 ret = do_quotactl(sb, type, cmds, id, addr);
 404         if (sb)
 405                 drop_super(sb);
 406
 407         return ret;
 408 }
 409
 410 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
 411 /*
 412  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
 413  * and is necessary due to alignment problems.
 414  */
 415 struct compat_if_dqblk {
 416         compat_u64 dqb_bhardlimit;
 417         compat_u64 dqb_bsoftlimit;
 418         compat_u64 dqb_curspace;
 419         compat_u64 dqb_ihardlimit;
 420         compat_u64 dqb_isoftlimit;
 421         compat_u64 dqb_curinodes;
 422         compat_u64 dqb_btime;
 423         compat_u64 dqb_itime;
 424         compat_uint_t dqb_valid;
 425 };
 426
 427 /* XFS structures */
 428 struct compat_fs_qfilestat {
 429         compat_u64 dqb_bhardlimit;
 430         compat_u64 qfs_nblks;
 431         compat_uint_t qfs_nextents;
 432 };
 433
 434 struct compat_fs_quota_stat {
 435         __s8            qs_version;
 436         __u16           qs_flags;
 437         __s8            qs_pad;
 438         struct compat_fs_qfilestat      qs_uquota;
 439         struct compat_fs_qfilestat      qs_gquota;
 440         compat_uint_t   qs_incoredqs;
 441         compat_int_t    qs_btimelimit;
 442         compat_int_t    qs_itimelimit;
 443         compat_int_t    qs_rtbtimelimit;
 444         __u16           qs_bwarnlimit;
 445         __u16           qs_iwarnlimit;
 446 };
 447
 448 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
 449                                                 qid_t id, void __user *addr)
 450 {
 451         unsigned int cmds;
 452         struct if_dqblk __user *dqblk;
 453         struct compat_if_dqblk __user *compat_dqblk;
 454         struct fs_quota_stat __user *fsqstat;
 455         struct compat_fs_quota_stat __user *compat_fsqstat;
 456         compat_uint_t data;
 457         u16 xdata;
 458         long ret;
 459
 460         cmds = cmd >> SUBCMDSHIFT;
 461
 462         switch (cmds) {
 463         case Q_GETQUOTA:
 464                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 465                 compat_dqblk = addr;
 466                 ret = sys_quotactl(cmd, special, id, dqblk);
 467                 if (ret)
 468                         break;
 469                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
 470                         get_user(data, &dqblk->dqb_valid) ||
 471                         put_user(data, &compat_dqblk->dqb_valid))
 472                         ret = -EFAULT;
 473                 break;
 474         case Q_SETQUOTA:
 475                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 476                 compat_dqblk = addr;
 477                 ret = -EFAULT;
 478                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
 479                         get_user(data, &compat_dqblk->dqb_valid) ||
 480                         put_user(data, &dqblk->dqb_valid))
 481                         break;
 482                 ret = sys_quotactl(cmd, special, id, dqblk);
 483                 break;
 484         case Q_XGETQSTAT:
 485                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
 486                 compat_fsqstat = addr;
 487                 ret = sys_quotactl(cmd, special, id, fsqstat);
 488                 if (ret)
 489                         break;
 490                 ret = -EFAULT;
 491                 /* Copying qs_version, qs_flags, qs_pad */
 492                 if (copy_in_user(compat_fsqstat, fsqstat,
 493                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
 494                         break;
 495                 /* Copying qs_uquota */
 496                 if (copy_in_user(&compat_fsqstat->qs_uquota,
 497                         &fsqstat->qs_uquota,
 498                         sizeof(compat_fsqstat->qs_uquota)) ||
 499                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
 500                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
 501                         break;
 502                 /* Copying qs_gquota */
 503                 if (copy_in_user(&compat_fsqstat->qs_gquota,
 504                         &fsqstat->qs_gquota,
 505                         sizeof(compat_fsqstat->qs_gquota)) ||
 506                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
 507                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
 508                         break;
 509                 /* Copying the rest */
 510                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
 511                         &fsqstat->qs_incoredqs,
 512                         sizeof(struct compat_fs_quota_stat) -
 513                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
 514                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
 515                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
 516                         break;
 517                 ret = 0;
 518                 break;
 519         default:
 520                 ret = sys_quotactl(cmd, special, id, addr);
 521         }
 522         return ret;
 523 }
 524 #endif
 525
 526
 527 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
 528
 529 /* Netlink family structure for quota */
 530 static struct genl_family quota_genl_family = {
 531         .id = GENL_ID_GENERATE,
 532         .hdrsize = 0,
 533         .name = "VFS_DQUOT",
 534         .version = 1,
 535         .maxattr = QUOTA_NL_A_MAX,
 536 };
 537
 538 /**
 539  * quota_send_warning - Send warning to userspace about exceeded quota
 540  * @type: The quota type: USRQQUOTA, GRPQUOTA,...
 541  * @id: The user or group id of the quota that was exceeded
 542  * @dev: The device on which the fs is mounted (sb->s_dev)
 543  * @warntype: The type of the warning: QUOTA_NL_...
 544  *
 545  * This can be used by filesystems (including those which don't use
 546  * dquot) to send a message to userspace relating to quota limits.
 547  *
 548  */
 549
 550 void quota_send_warning(short type, unsigned int id, dev_t dev,
 551                         const char warntype)
 552 {
 553         static atomic_t seq;
 554         struct sk_buff *skb;
 555         void *msg_head;
 556         int ret;
 557         int msg_size = 4 * nla_total_size(sizeof(u32)) +
 558                        2 * nla_total_size(sizeof(u64));
 559
 560         /* We have to allocate using GFP_NOFS as we are called from a
 561          * filesystem performing write and thus further recursion into
 562          * the fs to free some data could cause deadlocks. */
 563         skb = genlmsg_new(msg_size, GFP_NOFS);
 564         if (!skb) {
 565                 printk(KERN_ERR
 566                   "VFS: Not enough memory to send quota warning.\n");
 567                 return;
 568         }
 569         msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
 570                         &quota_genl_family, 0, QUOTA_NL_C_WARNING);
 571         if (!msg_head) {
 572                 printk(KERN_ERR
 573                   "VFS: Cannot store netlink header in quota warning.\n");
 574                 goto err_out;
 575         }
 576         ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type);
 577         if (ret)
 578                 goto attr_err_out;
 579         ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id);
 580         if (ret)
 581                 goto attr_err_out;
 582         ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
 583         if (ret)
 584                 goto attr_err_out;
 585         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
 586         if (ret)
 587                 goto attr_err_out;
 588         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
 589         if (ret)
 590                 goto attr_err_out;
 591         ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
 592         if (ret)
 593                 goto attr_err_out;
 594         genlmsg_end(skb, msg_head);
 595
 596         genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
 597         return;
 598 attr_err_out:
 599         printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
 600 err_out:
 601         kfree_skb(skb);
 602 }
 603 EXPORT_SYMBOL(quota_send_warning);
 604
 605 static int __init quota_init(void)
 606 {
 607         if (genl_register_family(&quota_genl_family) != 0)
 608                 printk(KERN_ERR
 609                        "VFS: Failed to create quota netlink interface.\n");
 610         return 0;
 611 };
 612
 613 module_init(quota_init);
 614 #endif
 615